With the miniaturizing trend of circuit patterns in progress associated with high integration of the semiconductor circuit, inspection measurement technique and failure analysis technique for the semiconductor manufacturing process has been increasingly recognized as important. Increase in the recording density of the hard disk device has placed more importance on the miniature structure or planarity of the pole part of the record/reproduction head, surface roughness of the recording medium, and measurement of a three-dimensional shape of stripe-like or dot-like structure of magnetism for further improving the recording density. The scanning probe microscope (hereinafter referred to as SPM: Scanning Probe Microscope) optimal for such usage has been widely known as an approach to measurement of the shape of the sample surface in the atomic order by scanning with the probe while having a fine probe tip brought proximal to or in contact with the sample surface.
Under the surface shape measurement using the SPM, the inspection region is restricted to a narrow region, for example, within several hundreds of micrometers square or less. Meanwhile, when measuring the very small area in the atomic order, the field of view ranging from several tens to several hundreds of nanometers is required to be measured with the accuracy in the atomic order or less. In this case, the mechanism for scanning with the probe is required to exhibit high positioning accuracy. Meanwhile, the broad range of approximately several tens of micrometers is required to be observed at high speeds in order to identify the measurement region. Furthermore, the local difference in height of the sample surface in the broad range of several hundreds of micrometers needs to be measured at high speeds.
Use of the SPM provides an advantage to ensure measurement of the three-dimensional shape of the sample surface with high resolution of approximately 0.1 nanometers. However, a certain amount of time is required to position the measurement point, and to measure at the point on the sample surface, thus failing to provide sufficient measurement throughput. In the manufacturing line for the device such as the semiconductor and the hard disk device, it is not used in-line (in the manufacturing process), and accordingly, it is mainly used off-line for the failure analysis. If measurement results of the SPM allow immediate detection of abnormality of the respective process devices, and feedback to the processing conditions of the respective process devices, manufacturing of the failure products may be minimized to improve the production yield on the manufacturing line. Therefore, implementation of the in-line SPM is highly expected. Upon implementation of the in-line SPM, it is essential to perform the processing (measurement) of the measurement points as large as possible for a unit time. The manufacturing line at present requires the processing time of 20 seconds or shorter, which may be converted into the measurement throughput corresponding to 30 WPH (wafer per hour) or more.
Generally, a piezoelectric device is used as an actuator of a mechanism for positioning the probe of the SPM on the sample with high-accuracy. For example, Patent Literature 1 discloses that the highly accurate SPM is realized by three axes X, Y and Z as parallel flat plates, which are individually driven by piezoelectric devices, and simultaneously, the probe position is controlled through measurement by means of a displacement gauge. A three-dimensional miniature scan mechanism as disclosed in Patent Literature 2 serves as another probe drive mechanism for improving positioning accuracy of the probe. This mechanism is configured to use three voice coil motors for driving three-axis stage provided with a Y-stage connected to an outer frame with an elastic member, and an XZ-stage (serving as both X-stage and Z-stage) connected to the Y-stage therein with the elastic member.
All the stages each consisted of the same member are integrally formed. The driving force of the voice coil motor is applied to each of those stages via a spindle. The respective spindles are configured to be always pressed in the operation direction of each of the stages in parallel regardless of displacement of the respective stages. For example, when only the Y-stage is operated, the elastic members for connecting the outer frame and the Y-stage are all elastically deformed uniformly. Therefore, there is no chance of application of the unnecessary force to the operation axis other than the Y-axis. This makes it possible to realize the probe scanning mechanism capable of controlling the probe positioning with respect to the three axes of the probe individually with high-accuracy. Patent Document 3 discloses the method of improving the stage positioning resolution using the piezoelectric device that is formed by connecting two types of those for fine and rough movements.
Patent Literature 4 discloses the SPM configured to improve the measurement throughput. Specifically, the sample surface position is detected by an approach sensor formed of an objective lens placed just above the probe, a laser diode, and a photodiode. The sample surface is brought into proximal to the tip position of the probe at high speeds to shorten the time taken for the SPM to start the measuring operation so as to improve the measurement throughput of the SPM. The SPM as disclosed in Patent Literature 3 has the objective lens just above the probe contact position on the sample. As the objective lens is placed just above the probe contact position on the sample, the measurement positioning on the sample is performed using an observation optical system, and then the measurement may be performed without moving the sample position. This makes it possible to improve the SPM measurement throughput.